Abstract: The harmonic screw type valve is driven by the double wave harmonic screw. It can transform circle movement to line movement for the closing and opening of the valve. The body and flange are airproofed by shell. The stern guiding device is used in the stop valve for guide. Radial distortion of the flexible component in the stop valve can be adjusted so as to ensure the joint depth between flexible screw thread trepanning circular groove and screw thread on the screw. Both flexible whorl cover and stern with screw are placed in flexible sealing shell. Flexible rolling bearing is composed of an outer ring and an inter ring. There is a raceway groove on the surface of the outer ring and the inter ring. The rolling elements in the groove are separated by cage, and the screw and stern are fixed by pin.